I found the level data of Sakura mode!
I attached a level editor (requires Java5 or newer) that can edit levels inside of game.exe.
0x7C120~ Field Map (each level has 200 bytes)
00=Empty
02=Red
03=Green
04=Purple
05=Blue
06=Orange
07=Yellow
08=Cyan
09=Gray
12=Gem Red
13=Gem Green
14=Gem Purple
15=Gem Blue
16=Gem Orange
17=Gem Yellow
18=Gem Cyan
19=Gem Gray
0x7D890~ Gimmick Type
00=None
01=Death Block
02=Roll Roll
03=*Transform
04=Color Block
05=Mirror Block
06=X-Ray
07=*180 Field
08=*Shot Gun!
09=*Hard Block
0A=*Laser
0B=*Dark Block
0C=*Nega Field
0D=Up Del Field
0E=Down Del Field
0F=Right Mov Field
10=Left Mov Field
11=Del Even
12=Free Fall
13=**Exchg Field (Freeze)
*:Long delay before the first piece appears
**:Freeze the game
0x7D8B0~ How often the gimmick happens
Does anyone know where the time limit is stored? I think it's hard-coded somewhere...